Photo/IllutrationTadao Yanase, a former executive secretary to Prime Minister Shinzo Abe, responds to a question at the Upper House Budget Committee in May. (Asahi Shimbun file photo)

Tadao Yanase, formerly a top aide to Prime Minister Shinzo Abe and central figure in the Kake Educational Institution scandal, is retiring from public life.

His departure at age 57 as vice minister for international affairs at the Ministry of Economy, Trade and Industry was greeted with skepticism by at least one opposition leader.

News of Yanase's pending retirement came July 24 in a ministry announcement of personnel changes.

Yanase's integrity was called into question following the release of a memo compiled by Ehime prefectural authorities in April 2015 when Yanase served as executive secretary to Abe.

The document concerned a meeting that prefectural officials had at the prime minister's office in Tokyo with Yanase.

It quoted Yanase as telling those present that the Kake Educational Institution's plan to open a veterinary medicine faculty in Imabari, Ehime Prefecture, was "a matter related to the prime minister."

The institution is headed by a close friend of Abe, which fueled suspicions among opposition party lawmakers that favoritism was behind the approval given to Kake Educational Institution to open the faculty.

After the Ehime prefectural government document came to light, Yanase was called before the Diet in May as an unsworn witness.

While he admitted to meeting with Kake Educational Institution officials on three separate occasions at the prime minister's office, he denied reporting on the matter to Abe or ever receiving instructions from the prime minister with regard to the Kake issue.

Opposition party lawmakers kept hounding Yanase because his responses failed to explain what lay behind the approval process for Kake Educational Institution.

In explaining the personnel changes, Hiroshige Seko, the economy minister, said the Kake issue had no bearing on Yanase's departure. He said Yanase was being replaced in part to turn over the baton to a younger generation.

However, his replacement as vice minister is Tatsuya Terazawa, also 57, and who entered the ministry in the same year as Yanase.

Yuichiro Tamaki, co-leader of the opposition Democratic Party for the People, was scathing about Yanase's retirement.

He said it allowed the Abe administration to bring the curtain down on the Kake scandal as it would be difficult to summon Yanase to the Diet as a private citizen.

(This article was written by Shinichi Sekine and Yuka Takeshita.)